On the suitability of Near-Infrared Systems for Next Generation Brain Computer Interfaces

Introduction Since Near-Infrared Spectroscopy (NIRS) was first reported in 1977 by Jobsis[1] as a new “window” into the body, it has found many uses within the biomedical field. Single channel near-infrared systems are most commonly used in clinical surroundings for transcranial cerebral oximetry in neonatal care, hematoma detection, and stroke patient monitoring. In addition to its clinical uses, near-infrared functional brain imaging is possible by detecting changing properties of tissue absorption and scattering associated with cerebrovascular response which naturally is coupled to neural activity. The current on-going development of multi-channel NIR systems, i.e. diffuse optical tomography (DOT), typically for brain imaging and breast imaging, portray the potential of NIR techniques for imaging applications. Mathematical modeling, simulation and experimental studies [2] have investigated light interaction with tissue and have resulted in a growing understanding of photon path propagation through tissue.